Drive mechanism of scanner

ABSTRACT

A drive mechanism of scanner, includes a delivery device, a first rotational speed motor and a second rotational speed motor. The said delivery device consists of a actuating wheel, a passive wheel and a circular conveyor belt wherein the circular conveyor belt is harnessed on actuating wheel and passive wheel respectively, the axes of the above-mentioned two passive wheels are attached to two ends of inner side diameter of actuating wheel, the output shaft of the first rotational speed motor is provided with a actuating skew gear and is engage with two passive skew gears respectively. The output shaft of the second rotational speed motor is provided with an actuating skew gear and is engage with two passive skew gears respectively. The drive mechanism drive two passive skew gears by means of the above-mentioned two motors so enable drive mechanism of the scanner to create specific rotational speed and scan document image.

FIELD OF INVENTION

[0001] This invention relates to the drive mechanism of scanner. More particularly, two different rotational speed motors are used to propel mutually drive mechanism in order to create scanner that has specific scan speed for image scanning.

BACKGROUND OF THE INVENTION

[0002] Scanner is a common peripheral equipment of computer, by means of internal image pick-up device to pick up document image and transfer the pick-up image into digital signal as input of computer and then perform image processing of the document.

[0003]FIG. 1A is a diagram showing scanner of prior art. The scanner of prior art device comprises a housing 12 with upper opening 11, transparent manuscript surface 13 that could carry weight of document and an image pick-up device 14 with image pick-up function. The said transparent manuscript surface 13 is combined with upper opening 11 of the housing 11. The said image pick-up device 14 is set within the housing and is promoted to scan image by drive mechanism (not shown) provided by scanner 1, wherein image pick-up device 14 may be optical path device of Charged Couple Device (CCD) or Contact Image Sensor (CIS).

[0004]FIG. 1B is a diagram showing scanner's drive mechanism of prior art. The drive mechanism 2 is mounted under the transparent manuscript surface, and promotes image pick-up device 14 to scan, comprising a scan path, a delivery device 22, a set of decelerated gears and a motor 24.

[0005] The scanning path 21 consists of a slip bar 211 and a sliding rail 212, the above slip and sliding rail parallel each other, and the image pick-up device 14 provides with a guide hole 141 and rotating wheel 142, and they cooperate with slip bar 211 and sliding rail 212 so as to scan back and forth in the scan path 21.

[0006] The delivery device 22 comprises a actuating gear 221, a passive gear 222 and a annular gear belt 223, wherein actuating gear 221 and passive gear are mounted in the two ends of the housing 12 respectively, the annular gear belt 223 is set on two gears 221, 222 respectively and parallel with scan path 21, furthermore the annular gear belt 223 combines with the image pick-up device 14.

[0007] The reduction gear set 23 is combined with motor 24 and actuating gear 221 respectively, its primary function is to provide appropriate reduction ratio so that rotational speed (torque) of motor 24 is reduced to appropriate extent and then communicate motive power to actuating gear 221.

[0008] Thus the scanning mode of drive mechanism is to promote the rotation of delivery device 22 by way of output power of motor 24 so that the annular gear belt 223 drives image pick-up device 14 to move back and forth in the scan path 21, and then scan document over the transparent manuscript surface.

[0009] However there are many design problems in the scanner 1 of the prior art. Since current consumers not only demand to increase the resolution of the scanner 1, also demand scanning speed as fast as possible simultaneously, but if the resolution of scanner is increased, speed of image processing becomes slow, then by adjusting reduction ratio of a reduction gear set or adopting higher rotational speed motor so as to increase scanning speed of scanner.

[0010] However whether DC motor or stepping motor, there both have definite specification and rotational speed (torque) range limit while left the factory, but all of the general companies purchase motor that has definite specification. Hence it is achieved by changing reduction ratio of reduction gear set, but if the wider the demanded resolution range of scanner, the larger the relative range of scanning speed; thus if adjust only reduction ratio change of reduction gear set that can not cover the needs of higher and lower scanning speed, so if differential gear theorem of car drive mechanism can be adopted and two scopes of rotational speed (torque) are provided to the said differential gear by means of two specifications motor simultaneously, furthermore drive mechanism of scanner is drove and the scanning speed scope of scanner is widened so as to match with scanning speed design of scanner under various resolutions.

SUMMARY OF THE INVENTION

[0011] The objection of this invention is to provide a drive mechanism of scanner. The drive mechanism is provided wider scope of scanning speed for scanner and matched with scanning speed design of scanner that has various resolutions.

[0012] The drive mechanism of scanner according to the present invention comprises a delivery device, two passive skew gears, a first rotational speed motor and a second rotational speed motor. The said delivery device consists of a actuating wheel, a passive wheel and a annular conveyor belt wherein the circular conveyor belt is harnessed on the actuating wheel and passive wheel respectively, the above-mentioned axes of two passive skew gears are attached to two ends of inside diameter of actuating wheel, the output shaft of the first rotational speed motor is provided with a actuating skew gear and is engage with two passive skew gears respectively. The output shaft of the second rotational speed motor is provided with an actuating skew gear and is engage with two passive skew gears respectively. The drive mechanism drive two passive skew gears by means of the above-mentioned two motors so enable drive mechanism of the scanner to create specific rotational speed and scan document image.

[0013] Wherein the above-mentioned two passive skew gears and two actuating wheels of two motors form into mechanism of differential gear. Due to the axes of two passive skew gears are attached to two ends of inside diameter of actuating wheel, also be based on features of differential gear, it is understood that average the sum of the first motor rotational speed and the second motor rotational speed equals to rotational speed of actuating wheel. Hence the motors of two different rotational speeds are used to mutually collocate and the particular or more appropriate rotational speed value is created in the actuating wheel so as to address the required scan speed design of the scanner under various resolutions.

[0014] These and other features and advantages of the present invention will be better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

BRIEF DESCRIPTION OF THE DRAWINGS

[0015]FIG. 1A is a scanner diagram of prior art.

[0016]FIG. 1B is a drive mechanism diagram of scanner according to the prior art.

[0017]FIG. 2 is a diagram of the drive mechanism according to scanner of the present invention.

[0018]FIG. 3 is a partial diagram of drive mechanism according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0019] Refer to FIG. 2, a diagram of the drive mechanism according to scanner of the present invention, the drive mechanism comprises a delivery device 31, two passive skew gears 32,33, a first rotational speed motor 34 and a second rotational speed motor 35.

[0020] The delivery device 31, which is used to drive image pick-up device 36 that moves back and forth in the scanner in order to scan image, consists of actuating wheel 311, passive wheel 312 and a annular conveyor belt 313, wherein the annular conveyor belt 313 is harnessed on actuating wheel 311 and passive wheel 312,the above-mentioned two passive skew gears 32,33 are attached to two ends of inside diameter of actuating wheel, the actuating wheel 311 and passive wheel 312 may be a fixed pulley or gear, and annular conveyor belt 313 may be a annular rope sheave or annular gear.

[0021] The said first rotational speed motor 34 is fixed within the scanner and its output shaft is perpendicular to the wheel face of actuating wheel 311, and is combined with actuating skew gear 341 on it, the said actuating skew gear 341 engages with the above-mentioned passive skew gears 32,33 respectively, the said second rotational speed motor 35 is fixed within the scanner and its output shaft is perpendicular to the wheel face of actuating wheel 311, and is combined with actuating skew gear 351 on it, the said actuating skew gear 351 engages with the above-mentioned passive skew gears 32,33, the above-mentioned two motors may be a DC motor or stepping motor.

[0022] Refer to FIG. 3, also to enable the more steady engagement between the above-mentioned two passive skew gears 32,33 and two motor 34,35, the invention further comprises a cross fixing stand 37, which is set between two passive skew gears 32,33 and two actuating skew gears 341,351. The said fixing stand is provided with 4 support bars that are mutually perpendicular, wherein two support bars 371,372 are connected fixedly to the axes of two passive skew gears respectively and the other support bars 373,374 are pivotally connected to the axes of two actuating skew gears 341,351.

[0023] The two passive skew gears 32,33 and two actuating skew gears 341,351 of drive mechanism engage mutually and form a mechanism that similar to differential gear of general car, the features of differential gear are described as follow:

[0024] a. The rotational speed of the first rotational speed motor is defined to ω₁.

[0025] b. The rotational speed of the second rotational speed motor is defined to ω₂.

[0026] c. The rotational speed of actuating wheel is defined to ω.

[0027] Thus the rotational speed of actuating wheel could be expressed to a half of rotational speed sum of the first rotational speed motor and the second rotational speed motor, that is, ω=(ω₁+ω₂)/2.

[0028] Therefore whether the outputted rotational speed (ω) of the said actuating wheel or not, the said drive mechanism can create particular or more appropriate rotational speed value in the actuating wheel 311 by means of mutual rotational speed collocation of the first rotational speed motors and the second rotational speed so as to address the required scan speed design of the scanner under various resolutions.

[0029] Besides, due to a certain range of rotational speed is provided by each type motor, but some motors' rotational speed output may be very steady within the said range, some enable motor to occur unstable phenomenon, therefore if rotational speed that is required by actuating wheel of scanner is within output range of motor rotational speed and but not steady, at this time scanning will result in scanner's instability while drive mechanism of conventional art is used; but if drive mechanism according to the invention is used, two steady rotational speed motors are selected to mutually collocate so as to create steady and meet required rotational speed output.

[0030] The drive mechanism of scanner according to the present invention has been described above by taking the case as better embodiment, but implementation scope of the present invention is not really limited to the scope of the embodiment described. All of the modifications, which are made by those whose familiar with the art without departing from the spirit of the invention, are belong to the scope of the invention. Thus the protective scope of the invention is based on the following claims. 

What is claimed is:
 1. A drive mechanism of scanner comprising: a delivery device consists of a actuating wheel, a passive wheel and a annular conveyor belt, the said circular conveyor belt is harnessed on the actuating wheel and passive wheel; two passive skew gears, the above-mentioned two passive skew gears are attached to two ends of inside diameter of actuating wheel; a first rotational speed motor, its output shaft is combined with a actuating wheel, the said actuating skew gear engages with the above-mentioned passive skew gears respectively and the output shaft of the said motor is perpendicular to wheel face of actuating wheel, and a second rotational speed motor, its output shaft is combined with a actuating wheel, the said actuating skew gear engages with the above-mentioned passive skew gears respectively and the output shaft of the said motor is perpendicular to wheel face of actuating wheel; wherein average the sum of the first motor rotational speed and the second motor rotational speed equals to rotational speed of actuating wheel.
 2. A drive mechanism of scanner according to claim 1 wherein the drive mechanism further comprising a cross fixing stand, the said fixing stand is provided with 4 support bars that are mutually perpendicular, wherein two support bars are connected fixedly to the axes of two passive skew gears respectively and the other support bars are pivotally connected to the axes of two actuating skew gears
 3. A drive mechanism of scanner according to claim 1, wherein the annular conveyor belt of drive mechanism is combined with image pick-up device so that drives it to scan back and forth.
 4. A drive mechanism of scanner according to claim 1, wherein the actuating wheel and passive wheel are fixed pulleys respectively, the said annular conveyor belt is an annular belt.
 5. A drive mechanism of scanner according to claim 1, wherein the actuating wheel and passive wheel are gears respectively, the said annular conveyor belt is an annular gear belt.
 6. A drive mechanism of scanner according to claim 1, wherein the above-mentioned first rotational speed motor and second rotational speed motor are stepping motors.
 7. A drive mechanism of scanner according to claim 1, wherein above-mentioned first rotational speed motor and second rotational speed motor are direct current motors.
 8. A drive mechanism of scanner according to claim 3, wherein the said image pick-up device is an optical path device with charge-coupled device.
 9. A drive mechanism of scanner according to claim 3, wherein the said image pick-up device is a contact image sensor. 